The Eiffel Tower wasn’t the brainchild of Gustave Eiffel.

Gustave Eiffel standing with another man near the top of the tower in 1889.
LIbrary of Congress

The structure may be named after Gustave Eiffel, but it was actually his senior engineers, Maurice Koechlin and Emile Nouguier, who designed the building. Eiffel wasn't overly interested in the project, but sent the engineers to the head of his company's architectural department, Stephen Sauvestre. With Sauvestre's edits, Eiffel got behind the final plans and bought the rights to the patent.

It was completed in record time.

Digging work on the site of the Eiffel Tower began on January 28, 1887. Over a year later, on April 11, 1888, the tower's first floor was completed, followed by the second floor on August 14, 1888. The final stage was completed on March 31, 1889 — just two years, two months, and five days after construction began.

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The tower was built as a symbol of modern science.

The completed second floor of the Eiffel Tower.
Roger Viollet/Getty

Or as Eiffel himself said, "not only the art of the modern engineer, but also the century of industry and science in which we are living." At the time that the tower was being built, another technology was also in its infancy — photography. As the tower was assembled, many photographers captured series of photographs to show the tower's construction.

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At the time of its construction, the Eiffel Tower was the tallest building in the world.

Parisians originally hated the Eiffel Tower.

Newspapers received angry letters that said the tower didn't fit into the feel of the city and there was a team of artists that rejected the plan from the get-go. One apocryphal story says that novelist Guy de Maupassant said he hated the tower, but ate lunch at its restaurant every day. When he was asked why, Maupassant replied that it was the only place in Paris where he couldn't see it.

Today, it is the most visited paid monument in the world.

The tower attracts almost 7 million visitors every year, 75% of them from other countries.

Unsurprisingly, 15.8% of visitors — the majority, when divided by country — are from France, according to visitor statistics. Outside of the country, Americans visit the most, making up 11.9% of the tower's visitors, followed by British tourists (7.5%).

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The Eiffel Tower has stood up to quite a lot during its lifetime.

A French soldier stands guard at the Eiffel Tower on November 15, 2015, following the Paris terror attacks.
David Ramos/Getty

It transmitted radio signals during WWI and during WWII the elevator wires were cut so that the Nazis could not use the tower (after Allied troops entered the city, the elevators were fixed). It has even survived a fire on its top floor.

The structure went gold at night in 1985.

When the monument was first built for the world fair, it was illuminated by 10,000 gas lamps. It wasn't until 1985 that the tower's golden lighting was introduced, with 336 projectors using sodium bulbs to cast the yellow-orange hue. In 2004, the projectors were replaced with more environmentally friendly ones.

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The beacon on the top can be seen from miles away.

Introduced on the countdown to the 21st century on New Year's Eve in 1999, the beacon and hourly light show have come to define the Eiffel Tower by night. The beacon is powered by automatic computer programs, sending two beams of light across a distance of 49.7 miles.

It’s not just a tourist attraction.

The Eiffel Tower has housed a newspaper office, a post office, scientific laboratories, a theater, and the first level becomes an ice rink every winter.

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Gustave Eiffel had a secret apartment on the third floor.

A wax model of Gustave Eiffel (right) with Thomas Edison in his apartment.Serge Melki/Flickr

Eiffel installed a tiny apartment near the top of the tower, where he entertained guests like Thomas Edison and kept a grand piano. Though he was reportedly offered attractive sums of money to sell the space, he never did. Today, visitors can see mannequin versions of Eiffel and Edison in the apartment through small windows.